Kiln for and method of treating ceramic and similar material.



1. T. umutawooo & 1. M. JUSTICE.-

KILN FOR AND METHOD OF TREATING CERAMIC AND SIMILAR MATERIAL.

APPLICATION Hm) APR. :1. I916- 1,224,978. v Patented May 8,1917.

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J. T. UNDERWOOD & l. M. JUSTICE. KILN FOR AND METHOD OF TREATING CERAMIC AND SIMILAR MATERIAL.

APPLICATION FILED APR. 1?. 1916. 1,224,978. Patented May 8, 1917.

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JOHN T. NDERwoon aNn ITHAMAR M. JUs'rIo or naY'roN, onro, assre ons To UNEEEwooD- ENGINEERING COMPANY, or n 'rEorr, MICHIGAN. a'oonronarron OF MICHIGAN.

KILN FOR AND METHOD OF TREATING CERAMIC A 1\T D SIMILAR MATERIAL,

Specification of Letters Patent,

latentedMay 8 1917-.

Application filed April 17, 1916. Serial No. 91,511.

To all whom it may concern:

Be it known that we, JOHN T. UNn'ii'iuvoon and ITHAMAR M. Jus'rion, citizens of the United States, residing at Dayton, in the county of Montgomery and State of Ohio, have invented certain new and useful Im provements in Kilns for and Methods of Treating Ceramic and Similar Material, of which the following is a specificatiom referones being had therein to the accompanying drawing.

This invention relates to kilns for, and a method of, treating ceramic and other similar material.

The object of one branch of our invention is to provide a construction by means of which the material within the kiln will be treated with perfect uniformity at a minimum cost. It is a further object of the invention to provide a means of varying the oxidizing or reducing nature of the fuel introduced into the kiln so that any desired color or condition of treatment of the ceramic or other-material may be secured at the will of the operator.

The first branch jqf our invention consists of the combination with a kiln or similar burning chamber, either permanent or built up from time to time, and of conduits to convey fuel and air of normal temperature'to the kiln. under pressure, and a means of mix ing the air and gas and the maintaining of the combined product under pressure in the kiln in an incandescent state.

The second branch of this invention consists of a process in which air and gas are introduced under pressure at 'or nearthe top of the kiln and maintained therein under pressure. The essential feature of the process is the introduction of the fuel at or in the top under pressure, the maintenance of that pressure in the kiln, and the expulsion of the spent or burnt gases at or near'the bottom of the kiln due to that pressure, after the fuel has passed from the upper to'the lower portion of the kiln around the material or through the interstices between the various portions of it.

Gases, or a combination or union of them, are maintained under pressure within the kiln, and, upon combustion, such gases become incandescent, with a result that the high heat generated by reason of their combustion and by reason of the feet tha the gases are under pressure, thoroughly treats thematerial'which is subjected to this heat. The heat is equally distributed to all parts of the interior of the kiln, because of the pressure to which the gases are subjected, driving them to every point within the kiln.

. The location 'of the burner at the top of the kiln has the advantage of an economical construction with all: the. parts readily .accessible and above ground, which facilitates adjustment and repair. By having the fuel composed of air and gas introduced at the top of the kiln, a large area is provided closely adjacent the mouths of the conduits introducing the air and gas, which permits of an extended area for the mixing of the air and gas, and a thorough and complete and homogeneous union of the various elements of the fuel and air before that fuel is forced through the interstices between the various parts of the material.

In the accompanying drawings, Figure l is a plan view of our preferred form of kiln; Fig. 2 is a vertical section through the same; Fig. 3 is a section of the same showing a modified form of burner thereon; Fig. 4 is a section of the same showing still another form of burner; and Fig. 5 is a detail of the air tube shown 'in Fig. 4.

' Referring to Figs. 1 and 2 we have shown the walls of the kiln at 1. The ground is excavated, as shown at 2, to support the kiln below -the general level thereof. A domeshaped roof 3 covers the side walls 1. The kiln, as'above described, is substantially air tight, there being no unnecessary openings. Locatedsli'ghtly below the general level of the kiln, as indicated at 4:, we have provided a diagonally ext-ending tunnel 5. This tunnel communicates with the interior of the kiln. In order to support the brick in proper position to insure the exhaust of the products of combustion through the tunnel 5 we have provided a series of transversely extending Walls of fire brick 6. These walls have spaces 7 therebetween, as shown in Fig. 1, and the spaces are spanned by placing rows of bricks on edge, the ends of the bricks resting upon adjacent walls 6. These bricks are indicated at 8 and are spaced apart, as shown at 8'. In this manner we have secured a foundation for the bricks to be baked and at the same time have formed this foundation in. such a manner that th prodnets of combustion and the gases can escape through the tunnel. The tunnel may be con 'nected with a chimney or stack of a well known kind. The bricks or other material to be baked are piled up upon the fire bricks 8 in a manner to insure perfect circulation of the heated gases therethrough. The arrangement of bricks is shown at 9 in Fig. 2. The tops of these bricks are covered by a fire brick deflector 10 located directly below the burner which will be described later. A space 11 is provided between the tops of the bricks and the roof 3. We contemplate using gaseous fuel and air for baking the materials and for this purpose we have provided a gas main 12 on one side and an air 1 main 13 on the opposite side. It will be 110- ticed that these mains are widely separated to eliminate any possibility of accident due to flying sparks and the like. The gas main may be connected to a series of kilns, such as described above, and a branch 14: is provided for each kiln, as shown. A vertically extending gas tube 15 connects the branch 1 1- with the interior of the kiln and is provided with. an opening 16. At the upper end of the tube 15 is a slide valve 17 to regulate the amount of gas flowing to the kiln. Around the base of the tube 15 we have provided a series of fire brick 18 provided with diagonally extending conduits 19. In the embodiment of the invention here shown there are eight of these fire bricks and eight conduits. However, the number may be varied to suit conditions. The air main 13 is provided with a branch 20 which terminates in a circular portion 21. The conduits 19 are connected with the circular portion 21 through connecting pipes 22. Each of the connecting pipes are provided with valves 23 for regulating the flow of air therethrough. In the embodiment here shown the valves are slide valves but any suitable valve may be used. Both the gas and air which is supplied through the mains 12 and 13 are under pressure. It is contemplated using producer gas for fuel but this invention is not to be limited to that particular gas. We have also provided normally closed peep holes 24 through which the condition of the brick may be observed and the supply of gas and air regulated accordingly.

By the construction above described the space 11 provides an extended area for the combustion and mixture of the fuel and air. The arrangement of the brick insures that the air and gas and the combination of them in an incandescent state will be evenly distributed throughout the bricks to heat the same and will finally escape through the tunnel 5. By admitting gas and air to the kiln under pressure the pressure within the kiln is maintained at all times considerably higher than the atmospheric pressure, there by preventing the admission of cold air through cracks and crevices within the kiln. After observation, if it is seen that one por' tion of the pile of brick is being heated more than others or not enough the valves controlling the several air conduits can be regulated. If the valves 23 on the left hand side shownin Fig. 2 are closed it will be seen that the greater part of the combustion will take place on the right hand side, thereby heating the brick on that side more than on the left. The air being admitted under pressure through the right hand passages 19 will be ejected toward the left and the gas combining therewith will cause combustion to take place more on the left than on the right. The amount of gas admitted can also be regulated through the valve 17 which can be of any suitable construction. Furthermore, the oxidizing and reducing proper ties of the flame can be varied by adjusting to different extents the valves 23 and the valve 17, an excess of air giving an oxidizing flame and an excess of gas giving a reducing flame, thereby affecting the baking brick to different extents.

In Fig. we have shown a modified form of burner. The general structure of the kiln is the same as that shown in Figs. 1 and 2. The burner, however, is different. The gas main 25 which is similar to the one above described has a branch 26 communicating with a suitable tube 27 having an opening 28 extending into the top of the kiln. The tube 27 is controlled by a suitable valve 29 to vary the amount of gas entering. The air main 30 is also provided with a branch 31 having a valve 32 an'c ,fpening into a tube 33 encircling the tube 27 and spaced therefrom. The tubes 27 and 33 are separated at the ends 34 to allow-air to enter the space between the roof and the brick, indicated at 35. It will be seen that the gas and air will mix at this point and burn. As in the form described above, the air and gas are caused to enter the space 35 at the top of the kiln under pressure, the effects being practically the same. The oxidizing and reducing effects of the flame can be varied by means of the valves 29 and 32.

In the form shown in Fig. 4-. the gas main 36 is connected by a branch 37 provided with an opening 38 controlled by a. slide valve 39 and communicating with a chamber 40. This gas chamber is connected by means of a pipe 11 with the kiln through an opening 42. The air main 13 is provided with a branch 14. having an elbow 45 connected at one end to the branch and at the other end to a fire clay air tube 46 which extends downwardly through the pipe 41. The lower end of the pipe 16 is flared and closed, as shown at 48, and the upper portion of the flared end is provided with a circumferential series of slots 49 through which the air is directed against the gas descending through the opening 42. As in the structures described in connection with Figs. 1, 2 and 3, the air and gas here are alsoforced into the kiln under pressures.

Ourprocess of treating ceramic material can be carried out by the structures above described and in that process we introduce gaseous fuel into the kiln at or near the top under pressure. The fuel burns in the kiln interior. The combustion of the fuel under pressure results in a very high heat due not only to the ordinary heat of combustion of the component elements of the fuel, but also to the fact that the fuel is introduced and n'iaintained in the kiln under pressure, thus increasing the temperature therein according to well known natural laws. In our process we employ a gaseous fuel which may consist of producer gas, Dowson gas, water gas or some such similar fuel in combination with air, both being forced into the kiln under pressure and maintained therein under pressure. e may employ either heated or cold air or air of a normal temperature. The use of air of ordinary temperature one ofthe achantages of our invention. The temperz ture resulting from the above union of air and gas under pressure when ignited is very great so that the gases in interior of the kiln become incandescent throughout, heating to the remotest portions thereof all material within it to be treated. The brick or ceramic material to be treated is arranged in such a manner that the fuel can have access to all sides thereof and in all parts of the kiln. The fuel completely fills the interstices between the portions of the material with its incandescent gases raising to incandescence even the surface of the material so treated. The gases filling the kiln are forced out of the tunnels or exits at or near the bottom of the kiln due to the pressure under which they are forced in near the top. Such gases'passing out are in the main spent or burnt products of combustion. The size of the tunnel is such, and the pressure by which the gases are forced into the kiln is so regulated, that the rate of exit is much lower than the rate of entrance of the gases, and as a consequence the pressure is maintained within the kiln above that of the surrounding atmosphere outside. In our process we regulate the supply of gas and air, and their proportion with respect to each other so that the oxidizing or reducing character of the igniting fuel can be adjusted at will through the manipulation of the valves described above. The hue or color of the material being treated can thus be determined with great accuracy and witheXtreme delicacy as well as with complete uniformity, due to the equal distribution of the ignited gases forced everywhere Within the kiln by reason of the pressure and the consequent exclusion of any incoming cold drafts due to the pressure being greater inside the kiln than outside of it.

Theuniformity of treatment of the ma terial and the ease of securing any variation or hue of brick or other ceramic material being treated, is a marked advance in the art, because it has heretofore been impossible to secure with any certainty similar results with similar means from different batches of the same material. Consequently, it has been necessary to treat a number of batches of material in order to secure a few which were alike.

The producer used for furnishing gas is of the well known type known as steamblown, water-sealed, although we do not mean to confine ourselves to any particular kind of gas or apparatus for producing it.

It is to be understood that the air and gas pressures must be so regulated as to be nearly equal to each other so as to balance .one another in the kiln; otherwise, one

might retard the other.

Having thus fully described our invention, what we claim as newand desire to secure by Letters Patent, is

1. The combination, with a kiln, of means located at the top thereof for artifically forcing into the same gas and air under pressure, said kiln being so constructed that the pressure therein will be in excess of the air pressure on the exterior of the kiln, whereby incoming drafts of cold air are prevented.

2. The combination, with a kiln, of means locatedat the top thereof for admitting gas and air under pressure and means for maintaining said pressure within the kiln above the normal atmosphere, said means comprising a restricted flue adjacent the bottom of the kiln to allow but retard the escape of the products of combustion.

3. The combination, with a kiln, of a burner located at the top centrally thereof and means for conveying to said burner gas and air under pressure in excess of the pressure in the exterior of the kiln.

4. The combination with a kiln, of a burner located adjacent the top thereof and arranged to distribute the heat of combustion uniformly throughout the kiln, means for conveying to said kiln gas and air under pressure, and means for maintaining the pressure within the kiln in excess of the air pressure on the exterior of the kiln, whereby incoming drafts of cold air are prevented.

5. The combination, with a kiln, of a burner arranged centrally of the top thereof, and conduits for conveying gas and air to said burner, one of said conduits being pro vided with a plurality of branch conduits communicating with the burner, and means for independently regulating each of said branch conduits.

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(3. The combination, with a kiln, of means adjacent the top thereof for forcing gas and air into the same under pressure, and means for regulating the relative amounts of gas and air admitted to said kiln.

7. The combination, with a kiln, of means adjacent the top thereof for forcing gas and air into the same under pressure, and means for regulating the'amount of gas and air admitted to said kiln for varying the intensity of the heat in various portions thereof.

8. The herein described process of treating amic material which consists in arranging the material within the kiln in a manner suitable to the heating thereof and then forcing gas and air through the top of the kiln under a pressure in excess of the air pressure on the exterior of the kiln where they may be burned and the gases maintained in an incandescent state.

9. The herein described process of treating ceramic material which consists in arranging the material. in a closed kiln in a suitable manner and then forcing gas andair through the top of the kiln under a pres sure in excess of the air pressure on the ex terior of the kiln and maintaining this pres sure in the kiln in excess of the air pressure on the exterior of the kiln.

10. The herein described process of treating ceramic material which consists in arranging the material within the kiln in a most suitable manner, forcing gas and air in the top of the kiln under a pressure in excess of the air pressure on the exterior of the kiln and then regulating the amounts of air and gas admitted to vary the oxidizing and reducing properties of the flame.

11. The herein described process of treating ceramic material which consists in foreing gas and air through the top of the kiln under a pressure in excess of the air pressure on the exterior of the kiln where the combustion thereof takes place and then regulating the intensity of the heat in various parts of the kiln.

12. The herein described process of treating ceramic material which consists in forcing gas and air through the top of the kiln under a pressure in excess of the air pressure on the exterior of the kiln and maintaining this pressure within the kiln in excess of the air pressure on the exterior of the kiln so that the incandescent mixture will fill the interstices between the portions of the material at all points within the kiln and the products of combustion will be forced out at apoint adjacent the bottom.

13. The herein described process of treating ceramic material which consists in piling the material to be treated in a kiln to allow the heat to have access to all parts thereof and leaving a space between the top of the material and the roof and then forcing a mixture of gas and air into the kiln at a point centrally of the roof, whereby the heat permeates all parts of the kiln.

14. The herein described process of treating ceramic material which consists in piling the material to be treated within a kiln to allow the heat to have access to all parts thereof, leaving a space between the top of the material and the roof, then forcing a mixture of gas and air into the kiln at a point centrally of the roof under a pressure in excess of the air pressure on the exterior of the kiln, maintaining this pressure within the kiln in excess of the air pressure on the exterior thereof and allowing the products of combustion to escape adjacent the bottom of the kiln.

15. The herein described process of treating ceramic material which consists in arranging the material within a closed kiln, forcing air and gas through the top thereof under pressure, causing the same to burn in the kiln under a pressure substantially above that necessary to create a current and allowing the products of combustion to escape adjacent the bottom of the kiln.

16. The herein described process of treating ceramic material which consists in forcing gas and air through the top thereof under pressure and causing the same to burn within the kiln under a pressure substantially above that necessary to create a current.

In testimony whereof, we aflix our signatures.

JOHN T. UNDERWOOD. I. M. JUSTICE.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington,- D. G. 

